CentOS 7 Docker Build

Docker is a popular platform for developing, shipping, and running applications in containers. CentOS 7 is a Linux distribution known for its stability and long-term support. In this article, we will explore how to build a Docker image using CentOS 7 as the base image.

Prerequisites

Before we start, make sure you have Docker installed on your system. You can download and install Docker from the official website: [Docker Official Website](

Building a Docker Image with CentOS 7

To build a Docker image with CentOS 7, we need to create a Dockerfile. The Dockerfile is a text document that contains all the commands needed to build a Docker image. Here is an example Dockerfile for building an image based on CentOS 7:

# Use the CentOS 7 base image
FROM centos:7

# Set the maintainer information
LABEL maintainer="your_email@example.com"

# Update the package repository and install some packages
RUN yum -y update && \
    yum -y install wget curl

# Set the working directory
WORKDIR /app

# Copy files into the container
COPY . /app

# Define the entry point for the container
CMD ["bash"]

Let's break down the Dockerfile:

  • FROM centos:7: This line specifies that we want to use the CentOS 7 base image for our Docker image.
  • LABEL maintainer="your_email@example.com": This line sets the maintainer information for the image.
  • RUN yum -y update && \ yum -y install wget curl: This line updates the package repository and installs wget and curl packages.
  • WORKDIR /app: This line sets the working directory inside the container to /app.
  • COPY . /app: This line copies the current directory into the /app directory inside the container.
  • CMD ["bash"]: This line specifies the default command to run when the container is started.

Building the Docker Image

To build the Docker image, create a directory with the Dockerfile and any other necessary files, then run the following command:

docker build -t my_centos_image .

In this command:

  • -t my_centos_image: This flag tags the image with a name (my_centos_image in this case).
  • .: This specifies the build context, which is the current directory.

Running the Docker Container

Once the Docker image is built, you can run a container based on that image using the following command:

docker run -it my_centos_image

This command will start a new container based on the my_centos_image image and open an interactive terminal session inside the container.

Conclusion

In this article, we have learned how to build a Docker image using CentOS 7 as the base image. Dockerfiles are essential for defining the steps needed to build an image, and they provide a reproducible way to create and share containerized applications. Experiment with different packages and configurations in your Dockerfile to customize your images according to your requirements. Happy containerizing!